There has been suggested a display device in which a viewer is allowed to see a real image of an object of view, i.e., real specular image formed in the air by using an imaging optical system of real specular image (see Patent Literature 1).
This display device includes an object of view arranged in a space opposite to the viewer, and the imaging optical system of real specular image for forming a real image of the object of view in a space in which the viewer exists. A real image of the object is formed at a position symmetrical to the object with respect to a plane of symmetry (element surface) of the imaging optical system of real specular image.